Adolescent alcohol use is strongly associated with many negative health outcomes and can increase risk for drinking problems later in life. The strongest predictor of adolescent alcohol use is affiliation with friends who also drink, use other drugs, or exhibit other problem behaviors (e.g., stealing, fighting). Currently, many studies examine friend problem behavior by asking adolescents to provide reports of their friends' behaviors; however, some research suggests that these reports may be inaccurate. While it is difficult to determine accuracy of report, report concordance is easily measured. No studies have examined variables that might predict report concordance, such as characteristics of the relationship (e.g. relationship quality; time spent with friends). This study compared adolescents' perceptions of their close friend's smoking, drinking, and deviant behavior to self-reports collected directly from the friends. Degree of association between perception and friend report was studied as a function of several relationship characteristics and demographic variables (e.g. age, gender) hypothesized to predict concordance. Results indicated that the statistically significant concordance between adolescent perception and friend self-report of smoking and drinking behavior was driven largely by agreement concerning the absence of behavior; adolescents were not sensitive in their perceptions of their friends' positive history of substance use. Concordance between adolescent perceptions and friend self-report of deviance was statistically significant but modest in magnitude, with most targets under-reporting their friend's involvement in deviant behaviors. Few variables predicted report concordance for the three outcome variables (smoking, drinking, and deviance), and those that did (age, adolescent's own problem behavior, negative relationship quality, and amount of time spent with friends) accounted for only a small amount of the variance. Implications for the assessment of friend influence on adolescent problem behavior are discussed
